Slurry composition for chemical mechanical polishing

Abstract

To provide a slurry composition for chemical mechanical polishing capable of simultaneously securing polishing rates for various film types including a polysilicon film, an oxide film, a nitride film and a copper film with a low solid content.SOLUTION: A slurry composition for chemical mechanical polishing includes two types of colloidal silica abrasive particles, a pH buffer, and a pH adjuster. The two types of colloidal silica abrasive particles include first colloidal silica abrasive particles having a neutral charge, and second colloidal silica abrasive particles having a negative charge.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a slurry composition for chemical mechanical polishing. [Background technology]

[0002] As semiconductor devices become more diverse and highly integrated, fine patterning techniques are being used, resulting in increasingly complex surface structures and larger step differences in surface films. In semiconductor device manufacturing, chemical mechanical polishing (CMP) is used as a planarization technique to remove step differences in specific films formed on substrates. In CMP, a wafer to be planarized is placed on a rotating plate, the wafer surface is brought into contact with a polishing pad, and the rotating plate and polishing pad are rotated while a slurry composition is supplied to perform the polishing process. Specifically, the slurry composition flows between the wafer surface and the pad. Mechanical friction between the abrasive particles in the slurry composition and the protrusions on the pad polishes the wafer surface, while chemical removal occurs through a chemical reaction between the chemical components in the slurry composition and the wafer surface. Generally, various types of slurry compositions are available depending on the type and characteristics of the material to be removed. There are currently a wide variety of slurries that selectively remove specific polishing layers, but conventional polishing compositions use single particles, making it difficult to ensure a polishing rate for a variety of film types, including polysilicon, oxide, nitride, and copper, despite their low solid content. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention aims to solve the above problems by providing a chemical mechanical polishing slurry composition that has a low solid content and can simultaneously ensure polishing rates for various film qualities, including polysilicon film, oxide film, nitride film, and copper film.

[0004] However, the problems that the present invention aims to solve are not limited to those mentioned above, and further problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0005] One aspect of the present invention provides a chemical mechanical polishing slurry composition comprising: two types of colloidal silica abrasive particles; a pH buffer; and a pH adjuster; wherein the two types of colloidal silica abrasive particles include first colloidal silica abrasive particles having a neutral charge and second colloidal silica abrasive particles having a negative charge. [Effects of the Invention]

[0006] The chemical mechanical polishing slurry composition according to the present invention simultaneously uses two types of charged abrasives, and has the effect of simultaneously ensuring the polishing rate for silicon oxide film and silicon nitride film even with a low solid content.

[0007] The effects of the present invention are not limited to the effects described above, but should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description of the present invention or the claims. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, various modifications may be made to the embodiments, and the scope of the patent application is not limited or restricted by such embodiments. It should be understood that all modifications, equivalents, and alternatives to the embodiments are included in the scope of the patent.

[0009] The terms used in the embodiments are merely used for the purpose of explanation and are not to be construed as limiting. A singular expression includes a plural expression unless the context clearly indicates otherwise. In this specification, the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, and should be understood as not precluding the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0010] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention pertains. Commonly used predefined terms should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as having an ideal or overly formal meaning unless expressly defined herein.

[0011] In addition, in the description with reference to the accompanying drawings, the same components are denoted by the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. In the description of the embodiments, if a detailed description of related known technology is determined to unnecessarily obscure the gist of the embodiments, the detailed description thereof will be omitted.

[0012] Furthermore, in describing components of the embodiments, terms such as first, second, A, B, (a), (b), etc. are used to distinguish the component from other components, and do not limit the essence, order, or sequence of the component.

[0013] Components having functions common to those included in any of the embodiments will be described using the same names in other embodiments. Unless otherwise specified, the description of one embodiment will be applied to the other embodiments, and detailed description will be omitted to the extent that they overlap.

[0014] Throughout the specification, when any part "comprises" any component, this does not mean that it excludes other components, but that it may further include other components.

[0015] One aspect of the present invention provides a chemical mechanical polishing slurry composition comprising: two types of colloidal silica abrasive particles; a pH buffer; and a pH adjuster; wherein the two types of colloidal silica abrasive particles include first colloidal silica abrasive particles having a neutral charge and second colloidal silica abrasive particles having a negative charge.

[0016] When only neutrally charged colloidal silica abrasive particles are used, a high oxide film removal rate can be ensured but a nitride film removal rate is reduced, and when only negatively charged colloidal silica abrasive particles are used, a high nitride film removal rate can be ensured but a sufficient oxide film removal rate cannot be ensured. However, the chemical mechanical polishing slurry composition of the present invention has the advantage of containing two types of colloidal silica abrasive particles with different charges as abrasive particles, thereby ensuring simultaneous removal rates for silicon oxide films and silicon nitride films even at a low solids content.

[0017] According to one embodiment, the two types of colloidal silica abrasive particles may be included in an amount of 0.01 wt % to 10 wt %, preferably 0.01 wt % to 5 wt %, and more preferably 1 wt % to 3 wt %, based on the total weight of the composition. If the content of the two types of colloidal silica abrasive particles is less than the above-mentioned lower limit, a sufficient polishing rate for silicon oxide and silicon nitride films may not be ensured. If the content exceeds the above-mentioned upper limit, a problem occurs in that scratches caused by the abrasive particles increase. The slurry composition according to the present invention has the advantage of being able to ensure a sufficient polishing rate for silicon oxide and silicon nitride films while limiting the solid content to a certain level or below, particularly a low level of 3 wt % or below.

[0018] The chemical mechanical polishing slurry composition according to the present invention can adjust the polishing rate for silicon oxide films and silicon nitride films by adjusting the weight ratio of two colloidal silica abrasives. According to one embodiment, the weight ratio of the first colloidal silica abrasive to the second colloidal silica abrasive may be 3:17 to 17:3, preferably 2:8 to 8:2, or 3:7 to 7:3. If the weight ratio of the first colloidal silica abrasive to the second colloidal silica abrasive is outside the above range, a sufficient polishing rate for oxide films cannot be ensured. If the weight ratio of the second colloidal silica abrasive is outside the above range, a sufficient polishing rate for nitride films cannot be ensured.

[0019] According to one embodiment, the diameter of the primary particles of the two types of colloidal silica abrasive particles may be 15 nm to 90 nm, preferably 20 nm to 70 nm, more preferably 25 nm to 55 nm, and the diameter of the secondary particles of the two types of colloidal silica abrasive particles may be 40 nm to 150 nm, preferably 50 nm to 130 nm, more preferably 55 nm to 110 nm. If the particle size of the colloidal silica abrasive particles exceeds the upper limit, there will be a problem of increased surface scratch defects, and if the particle size does not reach the lower limit, there will be a problem of insufficient nitride film polishing rate.

[0020] The pH buffer is used to prevent a sudden change in pH that occurs when preparing a composition by mixing abrasive particles, a pH adjuster, etc., and according to one embodiment, the pH buffer may include an organic acid, an amine-based compound, or both. Specifically, the pH buffer may include picolinic acid, nicotinic acid, isonicotinic acid, fusaric acid, dinicotinic acid, dipiconilic acid, lutidinic acid, quinolic acid, glutamic acid, alanine, glycine, cystine, histidine, asparagine, guanidine, hydrazine, ethylenediamine, formic acid, acetic acid, or the like. The dispersion may contain at least one selected from the group consisting of benzoic acid, oxalic acid, succinic acid, malic acid, maleic acid, malonic acid, citric acid, lactic acid, tricarballylic acid, tartaric acid, aspartic acid, glutaric acid, adipic acid, suberic acid, fumaric acid, phthalic acid, pyridinecarboxylic acid, and salts thereof, and preferably at least one selected from the group consisting of picolinic acid and glycine. The use of picolinic acid or glycine as a pH buffer has the advantage of ensuring dispersion stability.

[0021] According to one embodiment, the pH buffer may be contained in an amount of 0.01% to 2% by weight, preferably 0.01% to 1% by weight, based on the total weight of the composition.

[0022] The pH adjuster is a substance added to adjust the pH of the slurry composition to a desired value, and may be used in an appropriate amount within a range that allows the target pH to be achieved. The pH adjuster may be an acidic substance, a basic substance, or both. According to one embodiment, the acidic substance includes at least one selected from the group consisting of nitric acid, hydrochloric acid, phosphoric acid, sulfuric acid, hydrofluoric acid, bromic acid, iodic acid, formic acid, malonic acid, maleic acid, oxalic acid, acetic acid, adipic acid, citric acid, adipic acid, acetic acid, propionic acid, fumaric acid, lactic acid, salicylic acid, pimelic acid, benzoic acid, succinic acid, phthalic acid, butyric acid, glutaric acid, glutamic acid, glycolic acid, lactic acid, aspartic acid, tartaric acid, and salts thereof. The basic substance may be ammonium methyl propanol (AMP), tetramethylammonium hydroxide (tetramethylammonium hydroxide), or the like. hydroxide;TMAH), ammonium hydroxide, potassium hydroxide, sodium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, sodium bicarbonate, sodium carbonate, imidazole, and salts thereof.

[0023] According to one embodiment, the pH of the slurry composition of the present invention may be 1 to 4, preferably 1 or more and less than 3, or 1 to 2. If the pH of the composition does not reach the lower limit, the toxicity of the composition increases, and if the pH exceeds the upper limit, the polishing selectivity of nitride film to oxide film targeted in the present invention cannot be achieved.

[0024] The target film of the chemical mechanical polishing slurry composition according to the present invention may include a silicon oxide film and a silicon nitride film, or may include a polysilicon film, a silicon oxide film, a silicon nitride film, and a copper film, and may be a multi-type film including, for example, TSVs. Here, the composition may have a polishing rate of 300 Å / min or more for the polysilicon film, a polishing rate of 300 Å / min or more for the silicon oxide film, and a polishing rate of 600 Å / min or more for the silicon nitride film. The slurry composition according to the present invention has the effect of simultaneously using colloidal silica particles with two different charges, thereby ensuring polishing rates for both silicon oxide and silicon nitride films even at a low solids content.

[0025] The present invention will be described in more detail below with reference to the following embodiments. The following embodiments are provided for the purpose of illustrating the present invention, and the scope of the present invention is not limited thereto. <Embodiment>

[0026] Manufacturing example

[0027] Compositions of Embodiments 1 to 8 and Comparative Examples 1 to 13 were produced by containing 0.1 wt % picolinic acid as a pH buffer and 0.035 wt % nitric acid as a pH adjuster, and neutrally charged first colloidal silica particles and / or negatively charged second colloidal silica particles as shown in Tables 1 and 2 below. The jetter potential value of the first colloidal silica was 0±5 mV when measured at pH 2, and the jetter potential value of the second colloidal silica was −40 mV to −20 mV when measured at pH 2.

[0028] [Table 1]

[0029] Test example: Polishing rate evaluation The polishing rate evaluation was carried out using the compositions of Examples 1 to 8 and Comparative Examples 1 to 13 prepared above under the following evaluation conditions, and the results are shown in Table 2.

[0030] Evaluation conditions Test equipment: SP-01 / K1000 (KCT) Carrier rpm:78 Platen rpm:83 Wafer pressure: 2.0 R-ring pressure: 3.7 Slurry flow rate: 200ml / min Polishing pad: IC1000

[0031] [Table 2]

[0032] Referring to Table 2, it can be seen that even when the primary particle diameters and secondary particle diameters of the first colloidal silica and the second colloidal silica and the pH of the compositions are limited to the ranges specified in the present invention, the compositions of Comparative Examples 1 to 4, in which the weight ratio of the first colloidal silica to the second colloidal silica is outside the range of 3:17 to 17:3, are unable to ensure the oxide film polishing rate and nitride film polishing rate targeted by the present invention. In particular, it can be seen that if the weight ratio of the second colloidal silica does not reach the above range, a sufficient nitride film polishing rate cannot be achieved, and if the weight ratio of the first colloidal silica does not reach the above range, a sufficient oxide film polishing rate cannot be ensured.

[0033] Furthermore, with reference to Comparative Examples 6 to 8 and 10 to 12, it was confirmed that even when the weight ratio of the first colloidal silica to the second colloidal silica satisfies the range of 3:17 to 17:3, if the primary particle and secondary particle diameters of the first colloidal silica deviate from 15 nm to 90 nm and 40 nm to 150 nm, respectively, a sufficient oxide film removal rate cannot be ensured.

[0034] Furthermore, with reference to Comparative Example 13, it was confirmed that even when the diameter of the colloidal silica particles and the weight ratio of the first colloidal silica particles to the second colloidal silica particles were all within the range of one embodiment of the invention herein, when the pH was 3, the target oxide film removal rate could not be achieved.

[0035] Therefore, the slurry composition of the present invention has the effect of maintaining the polishing rate of poly-Si at a certain level or above, while simultaneously ensuring the polishing rate for oxide films and nitride films.

[0036] Although the embodiments have been described above, those skilled in the art may apply various technical modifications and variations based on the above. For example, the described techniques may be performed in an order different from that described, and / or the components of the described systems, structures, devices, circuits, etc. may be combined or combined in a form different from that described, or may be substituted or replaced by other components or equivalents, and still achieve suitable results.

[0037] Accordingly, other implementations, other embodiments, and equivalents of the claims are within the scope of the following claims.

Claims

1. Two types of colloidal silica abrasive particles; a pH buffer; A pH adjuster; Including, The chemical mechanical polishing slurry composition, wherein the two types of colloidal silica abrasive particles include first colloidal silica abrasive particles having a neutral charge and second colloidal silica abrasive particles having a negative charge.

2. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the weight ratio of the first colloidal silica abrasive particles to the second colloidal silica abrasive particles is 3:17 to 17:

3.

3. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the primary particle diameter of the two types of colloidal silica abrasive particles is 15 nm to 90 nm.

4. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the diameter of the secondary particles of the two types of colloidal silica abrasive particles is 40 nm to 150 nm.

5. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the pH buffer comprises an organic acid, an amine-based compound, or both.

6. The pH buffer may be picolinic acid, nicotinic acid, isonicotinic acid, fusaric acid, dinicotinic acid, dipicolinic acid, lutidic acid, quinolinic acid, glutamic acid, or the like. acid), alanine, glycine, cystine, histidine, asparagine, guanidine, hydrazine, ethylenediamine, formic acid, acetic acid, benzoic acid, oxalic acid, succinic acid, malic acid, maleic acid, malonic acid, citric acid, lactic acid 6. The chemical mechanical polishing slurry composition of claim 5, comprising at least one selected from the group consisting of tricarballylic acid, tartaric acid, aspartic acid, glutaric acid, adipic acid, suberic acid, fumaric acid, phthalic acid, pyridinecarboxylic acid, and salts thereof.

7. The pH adjuster includes an acidic substance, a basic substance, or both, The acidic substance includes at least one selected from the group consisting of nitric acid, hydrochloric acid, phosphoric acid, sulfuric acid, hydrofluoric acid, bromic acid, iodic acid, formic acid, malonic acid, maleic acid, oxalic acid, acetic acid, adipic acid, citric acid, adipic acid, acetic acid, propionic acid, fumaric acid, lactic acid, salicylic acid, pimelic acid, benzoic acid, succinic acid, phthalic acid, butyric acid, glutaric acid, glutamic acid, glycolic acid, lactic acid, aspartic acid, tartaric acid, and salts thereof; 2. The chemical mechanical polishing slurry composition of claim 1, wherein the basic substance comprises at least one selected from the group consisting of ammonium methyl propanol (AMP), tetramethyl ammonium hydroxide (TMAH), ammonium hydroxide, potassium hydroxide, sodium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, sodium bicarbonate, sodium carbonate, imidazole, and salts thereof.

8. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the two types of colloidal silica abrasive particles are contained in an amount of 0.01 to 10 wt % based on the total weight of the composition.

9. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the pH buffer agent is present in an amount of 0.01 to 2 wt % based on the total weight of the composition.

10. 2. The chemical mechanical polishing slurry composition according to claim 1, wherein the pH is 1 or more and less than 3.

11. The composition is suitable for polishing a silicon oxide film or a silicon nitride film. The polishing rate for the silicon oxide film is 300 Å / min or more, 2. The chemical mechanical polishing slurry composition of claim 1, wherein the polishing rate for the silicon nitride film is 600 Å / min or more.

12. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the film to be polished by the composition comprises copper.

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